Method of changing spindles in a double twist spindle frame



G. FRANZEN 3,410,079

METHOD OF CHANGING SPINDLES IN A DOUBLE TWIST SPINDLE FRAME Nov. 12, 1968 6 Sheets-Sheet 1 Original Filed Feb. 12, 1965 lgzen tor: Mu, r W

Nov. 12, 1968 G. FRANZEN 3,410,079

METHOD OF CHANGING SPINDLES IN A DOUBLE TWIST SPINDLE FRAME Original Filed Feb. 12, 1965 6 Sheets-Sheet 2 /gventor:

Nov. 12, 1968 G. FRANZEN 3,410,079

METHOD OF CHANGING SPINDLES IN A DOUBLE TWIST SPI NDLE FRAME Original Filed Feb. 12, 1965 I e Sheets$heet 5 In entor: wli iw Nov. 12, 1968 G. FRANZEN 3,410,079

METHOD OF CHANGING SPINDLES IN A DOUBLE TWIST SPINDLE FRAME Original Filed Feb. 12, 1965 6 Sheets-Sheet 4 Inventor: M @Jm, rm

G. FRANZEN Nov. 12, 1968 METHOD OF CHANGING SPINDLES IN A DOUBLE TWIST SPINDLE FRAME 6 Sheets-Sheet :5

Original Filed Feb. 12, 1965 d T m m P w A fl ds.

Fig. 5

In ven for.

G. FRANZEN 3,410,079

Nov. 12, 1968 METHOD OF CHANGING SPINDLES IN A DOUBLE TWIST SPINDLE FRAME 6 Sheets-Sheet 6 Original Filed Feb. 12, 1965 lnven (or:

United States Patent 8 Claims. ci. 57-156) ABSTRACT OF THE DISCLOSURE The method involves replacing the entire spindle upon which the package is exhausted or which has been affected by a yarn breakage by a completely prepared stand-by spindle already provided with a fresh winding-off package, while the double twist frame is in operation. At the same time as the spindle is changed the winding-on package and its holder may also be replaced by another. The reference in this context to replacement of the entire spindle is intended to mean that the spindle itself together with its bearings and the whorl as well as the protecting cup and the balloon limiter are thus replaced by another such spindle.

This application is a division of my copending application, Ser. No. 432,365, filed Feb. 12, 1965, now Patent No. 3,360,915.

The invention relates to a method of automatically operating double twist frames.

As known, the operation of double twist frames calls for the presence of at least one and possibly several operatives who must be at hand for changing the packages and for attending to yarn packages. If the requisite number of operatives is not available this usually causes considerable machine idle time and hence an unsatisfactory output of the machine.

An unpublished proposal already aims at reducing the manual working time on a running double twist frame for the purpose of economising in the time a spindle is idle before an operative is able to restart the affected spindle. The proposal consists in regarding the winding-off package and the associated winding-on package as being comprised in a single unit and in replacing both, irrespectively as to whether the trouble is due to a yarn breakage or to the winding-off package being exhausted.

For carrying out this replacement the earlier arrangement provides an assembly which is traversible in the machine and which can be called to the particular unit where a yarn breakage has occurred. Although this substantially reduces machine idle time it also involves the drawback that the traversible assembly can work at only one twisting unit at a time and that considerable time is still lost in the process of bringing up the assembly and in returning it to its stand-by position.

It is the object of the present invention to provide a method of operating a double twist frame which overcomes these drawbacks, and which is calculated to reduce machine idle time to an absolute minimum.

According to the invention the problem is solved by replacing the entire spindle upon which the package is exhausted or which has been affected by a yarn breakage by a completely prepared stand-by spindle already provided with a fresh winding-off package, whilst the double twist frame is in operation. At the same time as the spindle is changed the winding-on package and its holder may also be replaced by another. The reference in this context to replacement of the entire spindle is intended ice to mean that the low spindle itself together witht is bearings and the whorl as well as the protecting cup and the balloon limiter gas thus replaced by another such spindle.

With reference to the winding-on package, the invention proposes to change this together with its holder. In the extreme case the invention therefore proposes to change every part of a twisting unit that moves and that is driven, whereas the driving members themselves are and remain in their fixed positions in the machine frame without being changed.

The change is effected after the thread on a stand-by spindle has been threaded and its end possibly tied to the loose end of the winding-on package associated with the stand-by spindle or applied to the empty starter. The attendant operatives have plenty of time for doing this work because a spindle previously replaced for instance because it was empty, is transferred into a stand-by position and is not returned into operating position until the second spindle which is meanwhile in operation is affected by a yarn breakage or its package is exhausted.

For performing this novel method of operation the double twist frame must be equipped at each twisting station with a stand-by unit. As such it is already known to provide double twist frames with stand-by facilities. However, essentially these are merely places where fresh packages can be kept ready. According to the invention the get-ready positions are so contrived that they are suitable for the reception of a stand-by replacement spindle. Furthermore, the arrangement is such that the spindle which is in operative position and the stand-by spindle are both mounted on a common support such as a changeover beam which is rotatable about an axis in a plane perpendicular to the longitudinal axis of the frame. The axis of rotation of the change-over beam may be moulded on a movable carriage or slide. Alternatively the changeover beam may be mounted on a carrier that can be tilted along an arcuate path. Moreover, the spindle which is in operative position and the stand-by spindle may be mounted on a change-over beam that works on a shaft adapted to be raised and lowered, the raising motion being vertically upwards and possibly accompanied by a slight tilting motion.

Such arrangements permit a fully automatic changeover to be effected at every twisting station. The only work left to the operative is to get ready the winding-off packages and the starters or winding-on packages in the get-ready positions in good time, and to tie together the yarn ends if needed. Ample time should be available for this purpose so that, besides the many other advantages of the arrangement, the further advantage is gained that a single operative can attend to a larger number of spindles than is possible on other machines.

Furthermore, for double twist spindles with downward draw-off of the yarn a conveyor belt may be provided near the floor, on to which the full winding-on packages can be doifed, because in such an arrangement the winding-on position is preferably located at a lower level than the spindles.

The wound packages will usually be cheeses and cones, as required for use in creels, looms, knitting machines and the like. According to an unpublished proposal crosswound solid packages, i.e., solid cops, can likewise be used in conjunction with double twist spindles. In a double twist frame according to the invention the winding-on package may likewise be a cross wound solid package of such a kind.

The drawings are vertical sections of a twisting station illustrating several embodiments of the invention.

In FIG. 1 the upper end of a machine flame 1 in conventional manner carries a lead roller 2, a friction roller 3 and a traversing thread guide 4. 5 is the tubular core of the winding-on package.

Each twisting station, where the working double twist spindle 6 is located, also comprises get-ready facilities for the reception of a stand-by spindle 7. The spindle 6 which is in working position and the stand-by spindle 7 are both mounted on a common support, e.g., a change-over beam 8. The change-over beam 8 can turn about on axis and the axis of rotation is movable in a plane perpendicular to the longitudinal axis of the machine. More particularly it can be pivotably swung along the curved guideway 10. To this end the change-over beam 8 is tiltable about the centre of curvature 11 of the are formed by guideway 10.

The change-over beam 8 carries two spindles, the spindle at 6 being shown in section. This spindle comprises a whorl 12 and is mounted in conventional manner at 13 with the interposition of a member 14. Shaft 15 supports the turntable or spinner disc 16. The neck 17 of the table carries a double bearing 18 for the carrier 19 of the winding-off package. The winding-01f package itself is shown at 20.

21 is the balloon limiter. It comprises a member 22 which is rigidly connected to or integrally formed with the change-over beam 8. Parts of the balloon limiter which can be opened for convenient access to the spindle that is being got ready are attached to this member by hinges 23 (one of the hinges 23 can be seen on the balloon limiter surrounding the stand-by spindle 7, the hinge on the other limiter being hidden from view by the edge 24 of the package). The balloon limiters are fitted with permanent magnets 25 which co-operate with permanent magnets 26 attached to the package carrier 19. Permanent magnets 28 are likewise provided in the region of the abutting edges of the hinged parts 29. The latter permanent magnets cooperate with permanent magnets 27 which are likewise attached to the package carrier. The permanent magnets 28 also operate to keep the hinged parts of the balloon limiter 21 closed in operation.

The path taken by the thread is indicated by the discontinuous line marked 30. The thread is drawn ofi package 20 over-end and enters the central tube 31 from which it issues at the bottom at 32, leaving through the thread outlet opening 33. The thread slides over table 16 and forms a balloon 34. After having passed through the wire guide 35 it runs over a lead roller 2, the winding-on package being built up on tube 5 in conventional manner with the aid of the traversing thread guide 4.

The spindle is driven by a belt 36 which rotates the whorl 12. 37 is one of the usual tensioning rollers for the belt.

The running yarn /34 holds the wire guide in the position indicated in full lines. When the thread breaks or the entire yarn on package 20 has been unwound, the wire guide drops into position 35' shown in dotted lines. This causes an electric circuit to close and a solenoid 40 to be energised through contacts 38 and 39. The plunger of the solenoid lifts a catch 41, permitting pin 43 which is loaded by a spring 42 to press the pivotably mounted carrier arm 44 to the right in the drawing as far as pin 43 can advance. Consequently the carrier arm 44 and shaft 9 will tilt to the right far enough for the whorl 12 to lose contact with belt 36.

The movable locking pin 45 on the carrier arm 44 therefore strikes an abutment 46. At the same time a lamp 47 lights up and warns the attendant that the yarn has broken or that the winding-off package 20 is exhausted. The attendant depresses a pedal 48, releasting the locking pin 45 through rod linkage 49, and thus permits the carrier arm 44 to be tiltably pulled forward by hand along the arched guide 10 by the handle at 50. When a lever 51 strikes a cam 52 a pin 54 which is loaded by a spring 53 is withdrawn from locking position and releases the change-over beam 8. The attendant can therefore turn the change-over beam about axis 9. Twist spindle 6 is thus brought forward into the get-ready position, whereas spindle 7 that has been previously completely prepared moves into working position. A fresh winding-off package has already been mounted and the yarn threaded through the wire guide 4 35". The end of the thread is clamped at 55 in a convenient position.

When the change-over beam 8 has been turned and spindle 7 has thus been moved into the position previously occupied by spindle 6, the carrier arm 44 is simultaneously pushed back again on guide 10 by its handle 50. The locking pin 53 returns into locking posi tion because lever 51 rides off cam 52 and finally the arm clips into engagement behind abutment 46. The attendant need now merely tie the end of the broken thread to the beginning of the fresh thread or apply the beginning of the fresh thread to the fresh starter tube 5. The carrier 44 is then pushed home completely until notch 41 in catch 41 re-engages pin 45.

The described process has brought spindle 7 into Working position and this spindle now works whilst spindle 6 with the broken thread or the empty package 20 is in the stand-by position where it can be got ready. To permit all operations to be performed quickly without loss of time the outlet opening 33 from which the thread issues to form a balloon should always face forwards. In order to ensure that this is the case, the whorl 12 contains a permanent magnet 56 which in the illustrated embodiment co-operates with two permanent magnets 57 located in carrier 44. In view of the polarity indicated by letters S and N the whorl 12 and hence the spindle will stop in the required position with opening 33 facing forwards. The operative can therefore get this spindle ready as described and place the end of the threaded yarn into the clip at 55.

The fragmentary drawing FIG. 2 shows the bottom portion of the assembly according to FIG. 1, but moditied in that a lever 59 is pivotably attached to the carrier 44 at 58.

Together with a lever 61 which is hinged to guide arms 10 at 60, lever 59 forms a toggle lever system with a toggle hinge at 62. By pulling a handle bar 63 the entire carrier member 44 together with shaft 9 and spindles 6 and 7 can be moved into the position shown in dotted lines to permit the change-over beam 8 to be turned. Otherwise this arrangement functions in exactly the same way as described by reference to FIG. 1.

FIG. 3 illustrates the same arrangement as in FIG. 1 excepting that the winding-on tube 5 for winding a cheese is here replaced by a cross winding motion for building a solid cop. The twisted thread from the wire guide 35 runs to a feeder 200 and thence via a thread guide 201 to the funnel 202 which in a manner known to the art has a slit at the front and in which the cross wound solid cop 203 builds up in virtue of the action of the prismatic member 204. Bearing 205 rides up guideway 206 as the package builds up. The system is driven at 207 by a belt. Bearing 209 which can be moved by depressing a pedal 208 permits the solid cross wound package to be released for dotting.

In the embodiment according to FIG. 4 the general arrangement of the frame 1 is substantially the same as in MG. 1. However, a tubular longitudinal beam 64 is provided, and the bottom of the frame 1 has the form of a box 65 extending along the entire length of the frame.

In this embodiment a change-over beam 8 carrying spindles 6 and 7 is likewise Provided. The shaft 9 about which the change-over beam 8 can be turned extends beyond the point where the wire guides 35 and 35" are located and carries brackets 66 for the winding-on package 5.

The upper end of the extension 67 also carries two feeler levers 68. These feeler levers 68 atop the machine when the winding-on package on tube 5 has been built up to a given diameter.

The shaft 9 of the change-over beam 8 is mounted on a carriage 69. This carriage 69 has a cylindrical extension 70 supported on bail bearings 71 in a sleeve 72. The hollow cylindrical portion 70 of carriage 69 contains two opposed pistons 73 and 74. The hollow piston rod 75 of piston 73 is anchored in the end 76 of an outer protective cylindrical sleeve 77. The hollow interior of piston rod 75 communications through a pipe 78 with a magnetic valve 79. Moreover, a pipe 80 inside the hollow piston rod 75 likewise communicates through a second pipe 81 with magnetic valve 79. The magnetic valve is adapted to establish communication through a pipe 82 with a main pressure pipe 83 extending along the length of the machine. The other piston contains inside the hollow cylindrical extension 70 is loaded by two springs 84 and 85 and in addition it is provided with a rack 86 engaged by a pinion 87 which is axially slidable on shaft 9 in splines. The pinion is also fitted with a twin-tooth one-way clutch 88.

If the thread 30/34 breaks the wire guide 35 drops, closes a contact and thereby completes an electrical circuit for operating magnetic valve 79 through contacts 38/39. Before being operated the magnetic valve has been in a position in which pressure medium is admitted into pipe 78. The hollow cylindrical extension 70 is thus retained in its rearward position, keeping the whorl 12 in firm contact with belt 36. It may be advisable to provide an adjusting screw at 89 for controlling the pressure between belt 36 and whorl 12. Operation of the magnetic valve now admits pressure into pipe 81, whereas pipe 78 is exhausted. The pressure in chamber 90' is thus relieved through outlet 91. The pressure which simultaneously builds up in pipe 81 is transmitted through the pipe 80 inside the hollow piston rod 75 and causes chamber 93 to be pressurised. Consequently the hollow cylindrical extension 70 and carriage 69 are shifted into position 69' shown in discontinuous lines. This is possible because the springs 84 and 85 prevent relative movement of piston 74 until piston 73 makes contact with the end wall 94. When this is the case piston 74 can likewise shift to the right. The displacement of the latter piston pushes pin 95 against lever 96 which in turn releases pin 53 from the changeover beam 8. The rack 86 at the same time imparts r: tation to shaft 9 and turns the change-over beam 8 carrying the standby spindle 7 into the position previously occupied by spindle 6.

At the same time the tube and the package it carries as well as lever arm 66 participate in this rotation.

Carriage 69 can then return into position for operating the spindle. This is effected by a valve piston in the magnetic valve which reverses control by reference to time or to pressure. Locking pin 53 has returned into engagement with a ramp 97 and thus locks the change-over beam 8.

The pressure is chamber 93 is relieved, and piston 74 is therefore returned by springs 84 and 85 to the left. Rack 86 moves together with the piston, but the twin-tooth oneway clutch 88 permits an idle return of the rack. Pressure then rises again in chamber 90 and produces relative motion of piston 73 in the cylindrical sleeve 70 to draw back the carriage 69 to the left until screw 89 strikes its limit stop. All the parts of the system are thus back in their former positions.

During this motion the tube 5 or the package that has built up on this tube rides up an apron 98, the supporting arm being adapted to swing on its hinge at 99. The package or tube 5 bears down on friction roller 3 from above. In order to ensure that the acute angled deflection of the thread from the wire guide 35 to the lead roller 2 proceeds without trouble, a yarn deflector 100 made of corundum or the like is provided. Alternatively a small deflecting roller may be provided as indicated at 101.

The spindle 6 which had been in operative position is now at 7 in the get-ready position. The attendant rnust tie the thread or mount a fresh package and then apply the tied thread to the winding-on package 5. Whenthis work has been done the attendant must also press a ready but-ton. This button closes a circuit which permits the magnetic valve to initiate the required reciprocatory shift when the wire guide drops. Otherwise a single stroke would ensue, the whorl would merely be withdrawn from belt 36 and nothing further would happen. The provision of means for initiating the double stroke is convenient and necessary, particularly when the machine is to run at night when no personnel is available. The necessary manipulations at the get-ready station would in such a case have to be done when the morning shift begins. In the event of the thread breaking twice at one twisting station the spindle would be inactivated for the rest of the night.

In the embodiment illustrated in FIG. 5 the arrangement is such that the carriage '69 and its cylindrical extension 70 can move verticaly, guided by rollers 71 on a hollow cylinder 102. The hollow shaft 9 is concentrically mounted on the cylindrical extension 70 and the cylindrical guide 102. The shaft carries the supporting head for the wire guides 35 and 35' as well as the carrier arms 66 for the winding-on tubes 5 and 5.

Above the wire guide 35 is a deflecting roller 103. The axle pin of this roller also mounts a deflectable arm 104 which carries another roller 105 over which the thread runs on to the lead roller 2. When the thread breaks arm 104 drops into the dotted position 104' and closes a circuit which energises the magnetic valve 79 through contact 38 and a con-tact blade 39.

Pressure is thus admitted through pipe 106 into chamber 107 and piston 108 together with its piston rod moves upwards. The end of the piston rod carries a cam member 109 which is prevented by ball guides from rotating. The cam member 109 co-operates with a cam 111 built into the head 112 of the hollow rotatable shaft 9. Consequently piston 108 rnoves upwards together with carriage 69, the cylindrical extension 70 and the hollow shaft 9 to which the change-over beam 8 is attached. During this upward motion locking pin 53 is withdrawn from its seat against the resistance of its spring by a Bowden wire 113 which is provided for this purpose in the illustrated embodiment. The movement of the Bowden wire 113 is limited by an abutment 114. The rising cam faces 109 and 111 slidably engage and impress rotation upon the hollow shaft 9 about its vertical axis. The changeover beam 8 is thus turned and the prepared spindle 7 moved into the position previously occupied by spindle 6. This turning movement for exchanging the spindle takes place at the level indicated in the drawing by chain lines at 8'.

The preparation of the spindle and the tying together of the thread ends is then preformed in the same way as already described by reference to FIG. 4.

Since the magnetic valve 79 initiates a complete two stroke reciprocation of piston 108 when a thread breaks, the entire assembly descends again into its normal position as soon as the change-over beam 8 has turned and exchanged the two spindles. In order to ensure that the whorl 12 rides onto the belt 36 during the return without trouble,'it is advisable to give the whorl a conical taper at its bottom edge at 115.

As already described by reference to FIG. 4 it may also be desirable in this embodiment to provide a socalled ready button at the get-ready station, the button being operated by the attendant when she has completed the necessary manipulations for preparing the stand-by spindle.

The embodiment illustrated in FIG. 6 likewise comprises a change-over beam 8 which is raisedas is the case in the embodiment according to FIG. 5when the operative spindle is to be replaced by the stand-by spindle. However, it differs from the previous and the other embodiments in that a double twist spindle is provided in which the withdrawal of the twisted thread is downwards. The operative spindle 116 is shown in section. The other spindle 117 which is in standby position is shown merely in outline. The winding-off package 118 is mounted on a package carrier 119 which carries a protective cup 120. The latter has a cap 121 with an outlet at 122. The package carrier 119 is mounted on the turntable 124 in bearings 123. The plate 125 below the turntable 124 has an opening 126 which extends at least to 7 the centre of hollow shaft 127. The bottom end of the hollow shaft carries the whorl 128 and runs in bearing 129 in the change-over beam 8.

In this type of spindle the thread 130 is withdrawn from the package 118 and taken through the thread brake 131 into the top of cap 121 at 122. From here the ballooning thread 132 runs downwards to the turntable 124. Bearing against the table the thread then enters the hollow shaft 127 through opening 126 whence it is taken over deflector 133 to the lead roller 134. The thread then runs through the oscillating thread guide 135 on to the Winding-on tube 136. The core tube or rather the package that builds up on the tube is driven by friction roller 137.

The bracket 138 for the hinged carrier arm 139 of the winding-ontube is directly attached to the change-over beam 8. The deflecting roller 133 is similarly attached to the beam. On the other hand, the lead roller 134 and the friction roller 137 are mounted on the machine frame 1.

A bracket 140 on the machine frame 1 supports a longitudinal bar 141 which carries the tensioning rollers for the belt 143, of which one is visible at 142. The belt 143 is urged against the whorl 128 from the inside by tensioning roller 142.

The change-over beam 8 is fast on a pin 144. It forms part of the rotary piston 145. This rotary piston is located at the upper end of a hollow cylinder 146, which is provided with grooves 147 for bearing rollers 148. The rollers 148 guide the hollow cylinder inside sleeve 149 which also contains grooves so that cylinder 146 cannot rotate in relation to the sleeve 149. The sleeve 149 is fitted into socket 150 to which the piston rod 151 of piston 152 is likewise attached.

The stop motion 153 actuates a contact 154 when the thread breaks, causing the magnetic valve 155 to be energised. The pressure medium from a main pipe 83 is thus admitted via pipe 82 through the magnetic valve and flexible pipe 156 into the hollow interior of piston rod 151. Consequently pressure builds up in chamber 157 forcing cylinder 146 and the head 158 which is attached thereto upwards. During this upward movement the sloping face 159 rides over roller 160 and causes the head 158 as well as beam 8 to tilt sufficiently for the whorl 128 to lose contact with the belt 143. During the further upward motion a collar 161 on the extended locking pin 162 ascends to abutment 163 and the consequent relative movement releases pin 162 from its seat in the change-over beam 8. The load acting on the rotary piston 145 is now capable of rotating the change-over beam 8 to move spindle 116 out of operative position and the standby spindle 117 into operative position in its place.

Since the magnetic valve 155 has initiated a double piston stroke the hollow cylinder 146 and the parts attached thereto now begin to descend, ramp 159 riding on to roller 160 and returning the whorl 128 into operative contact with the belt 143. During the descending motion the core sleeve 136 or the partly built package already formed thereon rides down apron 164 and comes to rest on the friction roller 137 on which it bears obliquely from one side.

The attendant must now reload the spindle at the getready station, thread and tie the yarn and apply it to the winding-on tube. In order to facilitate threading of the yarn a needle 166 is provided which is guided in a slideway 165 and which can be pushed up the central tube 127 as far as the transverse channel in plate 125 where the beard 167 on the needle grips the yarn and carries it down when the needle is lowered. The needle 166 may be mechanically, pneumatically, hydraulically or electrically operated.

In these spindles in which the twisted yarn is taken downwards, permanent magnets are provided in conventional manner for arresting the package carrier in the desired position. Moreover, the whorl also carries a magnet which ensures that the spindle will always come to rest with the opening 126 in plate facing forwards. The advantage of this arrangement is that it constitutes a particularly simple assembly of low structural height. More particularly, the winding-on tube can be dotted from the position shown at 168 by opening the carrier and dropping the tube or the package on to a conveyor belt 169 underneath. This simple device also saves the manual work of dotting the fully wound packages.

What I claim is:

1. A method of operating a double twist frame winding thread from the winding-off package of a working spindle mounted thereon comprising: preparing in advance an entire stand-by spindle including bearing means and whorl means with a fresh winding-off package; and, upon exhaustion of the winding-01f package of the Working spindle or breakage of the thread of the winding-off package of the working spindle, replacing the entire working spindle by the prepared in advance entire stand-by spindle.

2. The method according to claim 1, which comprises exchanging winding-on tubes or packages and support means therefor simultaneously with exchange of the said spindles.

3. The method according to claim 2, which comprises threading the thread of the stand-by spindle before the spindles are exchanged.

4. The method according to claim 3, which comprises connecting the loose end of the yarn of the stand-by spindle to an associated winding-0n package or applying it to an associated winding-on core before the spindles are exchanged.

5. A method of replacing a working spindle in a double twist spindle frame by a prepared stand-by spindle provided with a fresh winding-off package, which comprises locating the two spindles in relation to one another, re-

leasing a working spindle from its drive in response to exhaustion of the winding-off package or breaking of thread and then reversing the position of the working spindle concerned and its associated stand-by spindle and operatively engaging the stand-by spindle for drive.

6. The method according to claim 5, which comprises interchanging one winding-on core for another simultaneously with reversal of the two said spindles.

7. A method of replacing a working spindle in a double twist spindle frame by a prepared stand-by spindle provided with a fresh winding-off package, which comprises locating the two spindles and, in response to exhaustion of the winding-off package or breakage of thread, automatically releasing the working spindle concerned from drive, reversing the positions of the said spindles and operatively engaging the stand-by spindle for drive.

8. The method according to claim 7, which comprises interchanging one winding-on core for another simultaneously with the reversal of the two spindles.

References Cited UNITED STATES PATENTS 2,442,775 6/1948 Nelson 57156 XR 2,584,096 1/1952 Thomas 5780 2,961,823 10/1960 Preston et a1. 57-583 3,172,247 3/1965 Chapuis et al 5758.52 3,316,698 5/1967 Franzen 5758.49 XR 3,319,410 5/1967 Franzen 5758.83 XR 1,823,374 9/1931 Porter 5752 1,868,154 7/1932 COppenOlle 57-52 1,983,000 12/1934 Paul 57-52 2,511,928 6/ 1950 Mansfield et, al 5752 FOREIGN PATENTS 1,139,417 10/1959 Germany.

FRANK I. COHEN, Primary Examiner. DONALD E. WATKINS, Assistant Examiner. 

